The present invention relates to a mechanism for preventing a liquid in a liquid storage tank from being splashed to an outside by a driving mechanism, and a component mounting apparatus with the liquid splash preventing mechanism.
For the component mounting apparatus, such a one as constituted, e.g., as shown in FIG. 6 has been known conventionally. The Component mounting apparatus 50 shown in FIG. 6 is a so-called rotary type, which mounts electronic components 51 to specified positions on a printed board 53 by transferring suction nozzles 55, for sucking and holding electronic components 51 to be mounted to the printed board 53, circumferentially between a component supply position 41 and a component setting position 42. The component mounting apparatus 50 is provided with a component supply device 52 for supplying electronic components 51 at the component supply position 41, a substrate support device 54 for supporting the printed board 53 as a mounting object to which electronic components 51 are to be mounted and for positioning the printed board 53 to the component setting position 42, an index unit 59 having a mounting head 56 to which the suction nozzles 55 are installed to be movable up and down whereby each suction nozzle 55 is disposed at the component supply position 41 and at the component setting position 42 by intermittently rotating the mounting head 56, and a lift mechanism 45 for moving the suction nozzles 55 up and down.
The component supply device 52 is constructed in an arrangement in which a plurality of component supply cassettes 57 for storing and supplying electronic components 51 are arranged correspondingly to types and a number of the electronic components 51 required for mounting to the printed board 53. The device 52 moves the component supply cassette 57 holding a desired electronic component 51 so that the electronic component 51 required for mounting is disposed at the component supply position 41, thereby supplying the desired electronic component 51.
The substrate support device 54 has an XY-table 58 for positioning and supporting the printed board 53. For mounting a predetermined electronic component 51 to a component mounting position on the printed board 53, the XY-table 58 moves in two, i.e., X and Y directions orthogonal to each other in a plane to bring the component mounting position to be opposite to a suction nozzle 55 disposed at the component setting position 42.
The mounting head 56 is adapted to move the suction nozzle 55 down while controlling the suction nozzle 55 to a necessary height in accordance with an arrangement position of the suction nozzle 55 so as to suck the electronic component 51 at the component supply position 41 or to mount the electronic component 51 at the component setting position 42.
The index unit 59 is a device for intermittently rotating the mounting head 56, and has the mounting head 56 fitted to a first output shaft 59a projecting downward from the index unit 59. Therefore, when the mounting head 56 is intermittently rotated by rotation of the first output shaft 59a, the suction nozzle 55 fixed to the mounting head 56 sucks and mounts an electronic component 51 at each of stop positions. A rotary member 60 is fitted to a second output shaft 59b of the index unit 59.
The lift mechanism 45 is a device which is arranged adjacent to the index unit 59, and moves the suction nozzle 55 up and down in accordance with the intermittently rotating operation of the index unit 59. The lift mechanism 45 is constituted in a structure as described below.
An oil tank part 77 with a lubrication oil 78 filled inside is installed to a driving part 66 of the lift mechanism 45. A cam shaft 62 is fitted rotatably to the oil tank part 77, to which a rotary member 63 is fitted at an outside of the oil tank part 77, and a plate cam 65 is fixed inside the oil tank part 77. The plate cam 65 and a roller 69 to be depicted later soak in the oil 78. A belt 61 is hung between the rotary member 60 of the index unit 59 and the rotary member 63, whereby the cam shaft 62 rotates following rotation of the rotary member 60 of the index unit 59.
Inside the oil tank part 77, there is arranged a first driving lever 68 which can rotate about a mounting shaft 67 set to the oil tank part 77 and has an approximately Y-shaped form caused by first, second and third arms. The roller 69 which is to track an outer surface of the plate cam 65 is mounted rotatably to a leading end of first arm 68a of the first driving lever 68. At the same time, one end of a spring 70 attached to the oil tank part 77 is in contact with second arm 68b of the first driving lever 68. The roller 69 is accordingly pressed to the outer surface of the plate cam 65 and is enabled to surely track the outer surface of the plate cam 65 through a rotational action of the first driving lever 68 about the mounting shaft 67 by an urging force of the spring 70. In consequence, the first driving lever 68 traces a shape of the outer surface of the plate cam 65 rotating in accordance with rotation of the rotary member 60 of the index unit 59.
One end of a first coupling link 71 is connected to a leading end of third arm 68c of the first driving lever 68. Another end of the first coupling link 71 is connected together with one end of a second coupling link 73 to a link block 72 by a coupling pin 74. Another end of the second coupling link 73 is connected to one end of a second driving lever 75 supported rotatably to a frame member of the component mounting apparatus 50. A roller 76 for lifting is attached rotatably to another end of the second driving lever 75. The roller 76 for lifting is engaged with a part of the mounting head 56 and constituted so as to follow oscillation of the second driving lever 75.
As described earlier, the plate cam 65 and the roller 69 soak in the oil 78 in the oil tank part 77. A leading end part of the third arm 68c of the first driving lever 68 installed to the inside of the oil tank part 77 projects outside of the oil tank part 77 through an opening part 77a formed in the oil tank part 77. The opening part 77a is provided with an oil guard 80 for preventing the oil 78 in the oil tank part 77 from scattering to the outside through the opening part 77a. 
The conventional component mounting apparatus 50 constituted as above operates in the following manner.
The first output shaft 59a starts to be intermittently rotated by the index unit 59, thereby starting to intermittently rotate the mounting head 56 as well. The suction nozzle 55 attached to the mounting head 56 sucks and holds the electronic component 51 automatically supplied from the component supply device 52, and is displaced by the mounting head 56 from the component supply position 41 to the component setting position 42 through the above intermittent rotation.
Simultaneously with the above displacing operation, the rotary member 63 attached to the oil tank part 77 is also rotated via the belt 61 by rotation of the second output shaft 59b of the index unit 59 and the rotary member 60. When the cam shaft 62 consequently rotates in the oil 78 of the oil tank part 77, the cam plate 65 rotates similarly. Accordingly, the roller 69 pressed to the outer surface of the plate cam 65 tracks the outer surface of the plate cam 65, whereby the first driving lever 68 oscillates about the mounting shaft 67.
This oscillation of the first driving lever 68 oscillates the link block 72 about the coupling pin 74. The first and second coupling links 71 and 73 move up and down while being restricted by oscillation of the link block 72. The second driving lever 75 oscillates in accordance with the up and down movement of the first and second coupling links, and the roller 76 for lifting of the second driving lever 75 moves up and down accordingly. A part of the mounting head 56 engaged with the roller 76 for lifting follows the up and down movement, hence moving the suction nozzle 55 up and down. In the manner as above, the suction nozzle 55 is moved down at, e.g., the component setting position 42 and the electronic component 51 is mounted to the component mounting position on the printed board 53.
In the above-described conventional arrangement, the oil 78 whirled up by operation of the plate cam 56 and the roller 69 inside the oil tank part 77 adheres to the first driving lever 68 in its entirety and the guard 80, and probably splashes to the outside through the opening part 77a of the oil tank part 77 as a result of oscillation of the first driving lever 68. The oil 78 may be turned into spray when stirred by the plate cam 65 and the roller 69, thereby scattering to the outside of the oil tank part 77. Also, the oil 78 may stream down the first and second coupling links 71 and 73, and the like, to unfavorably drop onto the suction nozzle 55 and the printed board 53.